Mamoru Manita

Coronary Sinus Recordings of Double Potentials Associated with Retrograde Conduction Through Left Atrioventricular Accessory Pathways

Introduction: In some patients with left AV accessory pathway (AP), double potentials are recorded along the coronary sinus (CS) during retrograde AP conduction only. This electrophysiologic study was performed to clarify the origin and clinical significance of double potentials in 11 patients.

Typical Atrial Flutterlike Tachycardia Developing After Inferior Vena Cava-Tricuspid Annulus Isthmus Ablation

A 48-year-old man was admitted to our hospital for evaluation of paroxysmal tachycardia. The 12-lead electrocardiogram (ECG) during the spontaneous tachycardia showed the typical “sawtooth” pattern with negative P waves in surface leads II, III, and aVF, supporting diagnoses of typical atrial flutter (Fig. 1A). The 12-lead ECG during sinus rhythm was normal. The patient suffered from no serious diseases and had no history of surgery. Echocardiography revealed normal left ventricular function. Because of recurrent attacks of palpitation despite antiarrhythmic therapy, the patient underwent electrophysiological study and an attempt at radiofrequency (RF) catheter ablation. During electrophysiological study, the clinical tachycardia was reproducibly induced by rapid atrial pacing near the ostium of the coronary sinus. However, no other atrial tachyarrhythmias were inducible, even by more aggressive induction protocol methods from several atrial pacing sites. Atrial activation mapping during the tachycardia recorded by a Halo catheter (Cordis-Webster, Miami, FL, USA), revealed a counter-clockwise activation sequence along the tricuspid annulus (Fig. 1B). Furthermore, entrainment mapping from several atrial sites along the tricuspid annulus demonstrated typical counter-clockwise atrial flutter, as evidenced by a postpacing interval equal to the cycle length of atrial flutter at all pacing sites. RF ablation was performed to create a linear lesion across the tricuspid annulus-inferior vena cava isthmus. The typical atrial flutter terminated during ablation. After confirmation of complete bidirectional block through the isthmus, rapid atrial burst stimulation reproducibly induced a new tachycadia (Fig. 1C). Morphology and polarity of the atrial complexes and its atrial activation sequence along the tricuspid annulus were comparable to those recorded during counter-clockwise typical atrial flutter induced before isthmus ablation, but the atrial cycle length of this postablation tachycardia (278 ms) was longer than that of the treated tachycardia (235 ms, Fig. 1C and D). What is the underlying electrophysiological mechanism of the new, typical atrial flutterlike rhythm developing after isthmus ablation?

Myocardial bundles with slow conduction properties are present on the left interventricular septal surface of normal human hearts.

Introduction: The aim of this study was to examine the electrophysiologic characteristics of the normal left interventricular septum (LIVS).

Atrioventricular nodal re-entrant tachycardia with two functionally discrete fast pathways.

We present a case with two forms of atrioventricular nodal re-entrant tachycardia (AVNRT) that revealed similar H — A – V sequences, but could be differentiated only by their retrograde atrial activation sequences. Both tachycardias were induced following anterograde slow pathway conduction, suggesting the slow pathway as the anterograde limb of the reentry circuit. The earliest atrial activation site of one form was in the same region of the bundle of His as that of the common type of AVNRT, while that of the other form was the ostium of the coronary sinus. Properly timed extra-stimuli delivered from the atrium or ventricle during the latter tachycardia penetrated through the fast pathway without resetting the tachycardia cycle length. These rare phenomena suggest the existence of two functionally discrete fast pathways, of which the alternative pathway alters to become the more predominant retrograde limb according to time and circumstances.

Discrimination between His‐bundle and the Right Bundle Branch during Electrophysiologic Studies

Background: The purpose of this study was to identify the His‐bundle (HB) versus right bundle branch (RBB) during electrophysiologic studies, using the V3 phenomenon, and to compare the timing of HB versus RBB potentials of sinus cycles (His‐ventricular [H‐V] interval).

Respiratory Collapse of the Inferior Vena Cava Reflects Volume Shift and Subsequent Fluid Refill in Acute Heart Failure Syndrome.

BACKGROUND Fluid redistribution rather than fluid accumulation plays an important role in the development of acute heart failure (HF) syndrome. Patients with fluid redistribution develop acute HF without prominent volume overload. We investigated volume status by measuring the diameter of the inferior vena cava (IVC) and examining variations in hemoglobin and hematocrit. METHODSANDRESULTS Seventy-four consecutive patients admitted for acute HF syndrome were analyzed. Blood tests and measurement of IVC diameter after stabilization of respiratory distress were performed on admission and were repeated after 24 h. IVC collapsibility index (IVC-CI) was calculated as (maximum IVC-minimum IVC)/maximum IVC. According to the initial IVC-CI, the patients were divided into the collapse group (IVC-CI ≥0.5: n=34) and the non-collapse group (IVC-CI <0.5: n=40). Initial blood pressure was higher in the collapse group (P<0.001). Although 24-h urine volume did not differ between the groups, hemoglobin (P<0.001) and hematocrit (P<0.001) decreased significantly in the collapse group but not in the non-collapse group after 24 h. Furthermore, IVC-CI significantly decreased in the collapse group after 24 h (P=0.003). CONCLUSIONS In acute HF syndrome, IVC-CI ≥0.5 on admission suggests a volume shift from the central vein into the pulmonary vasculature. Fluid refill occurs within 24 h after admission. This observation could be helpful in selecting strategies for diuretic use. (Circ J 2016; 80: 1171-1177).

Focal Pseudo-Atrial Fibrillation after Radiofrequency Ablation of Focal Atrial Tachycardia

Focal pseudo‐atrial fibrillation (AF) developed in a 30‐year‐old woman after radiofrequency (RF) ablation of focal atrial tachycardia (AT) originating from the coronary sinus ostium. Programmed atrial stimulation occasionally induced, accelerated or terminated AT, and a spiky prepotential preceded the earliest atrial electrogram at the AT focus. After the first RF application, repetitive bursts of accelerated tachycardia developed, mimicking AF on the surface ECG. An additional RF application where the spiky prepotential was observed, eliminated the focal pseudo‐AF.

A thrombus stuck in the ostium of the coronary artery

A 55-year-old male ex-smoker was admitted to our hospital with a 2-h history of anterior chest and back pain. His vital signs and serum biomarkers including troponin I were normal. An electrocardiogram showed atrial fibrillation without an ST-elevation. Plain computed tomography (CT) imaging revealed the high density in the proximal …

Bundle Branch Reentrant Ventricular Tachycardia with Two Distinct Components of QRS Complex due to Simultaneous Dual Transseptal Conduction

Dual Transseptal Conduction in Bundle Branch Reentry. We report the case of a patient with bundle branch reentrant ventricular tachycardia having two distinct components of the QRS complex due to simultaneous dual transseptal conduction. The macroreentrant circuit consisted of anterograde conduction down the left bundle branch and retrograde conduction up the right bundle branch. Extensively injured myocardium in the interventricular septum isolated the two separate transseptal passages, which exhibited a “fast” and “slow” conduction property, respectively. The QRS configuration resulted from a wavefront propagating from the left bundle branch via “fast” transseptal conduction, followed by another more delayed wavefront propagating via “slow” transseptal conduction, which played an important role in determining this unique QRS morphology.